This narration prescribes that this dhikr should be recited between subh sawdiq (the break of dawn) and the fard of Fajr.

‘Alamah ‘Iraqi (rahimahullah) writes: “This has been recorded by Imam Mustaghfiri in his book on supplications on the authority of Sayyiduna Ibn ‘Umar (radiyallahu‘anhuma)” Imam Mustaghfiri then expressed reservation in its authenticity.

(See Sharhul ihya, vol. 5 pg.13)

However, because of the existence of other supporting chains as well as the following authentic Hadith, Al-Muhaddith Ibn ‘Arraq (rahimahullah) has concluded that the Hadith in question is weak (i.e, suitable for practice)

(Tanzihush Shari’ah, vol.2 pg.318)

The authentic support I was referring to is a lengthy one in which Nabi Nuh (‘alaihis salam) advises his son to recite ‘subhanallahi wa bi hamdihi’ as this is the means through which the rest of the creation acquires their sustenance. This is supported by the verse in the Quran; ‘Everything glorifies His praise (tasbih) but you do perceive their tasbih’ (Surah Isra, verse: 44)

Note: This Hadith doesn’t specify when to recite the above dhikr. One could therefore recite it whenever possible, preferably in the morning, as we are encouraged to start our search for livelihood early in the morning.